Carburetor



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IIGHIGAN, ASBIG'NR TO' GENERAL 'MTRS G03- PORLTIOHQ' 0I DIIBOIL' IICHIGAI, i

A. UOBPGRATION Oi* ,DELAWARE Appnnuqn mii-:p17 s1, 191e. serial ira. einem One well known type of carburetor.- com- A prises a strangle tube around the upper end of extending y down a nozzle structure and provided with a tubular lair valve movor less auxiliary air to ture 1n accordance with engine,

as a whole to admit more the primary mixthe speed of the 1 said air valve being actuated by the difference in pressure between the space immediately around Y above a disc-like fixture c depending into the strangle tube.

, One object of the presentinvention is to improve this type of carburetorV so as to obtain both more lean or economical the nozzle and that arried thereby and a correct idling mixture and a mixture at intermediate engine speeds. This I accomplish in the present instance by means of one or more by-pass passages throng h the strangle tube so arranged as to .admit air pressure to the' spaceabove the nozzle at the intermediate throttled speeds,

said by-p'ass being positioned to admit relatively less air pressure under conditions of closed throttle such asin idling. Thus substantially the vpass directly air supply is made to entire about the nozzle in idling and under conditions of low engine suction; when the suction increases to that corresponding to the intermediate throttled speeds, the by-pass passages admit air pressure andadiluting sup-` ply of strangle .tube in' addition 'to the lower edges of the auxiliary enters past air valve proper, thereby air to the primary mixture in the that which reducing the suction effective, on the nozzle, which, in' turn, tends to reduce the amount'of fuel delivered and .to establish a more lean,

mixture.'

Another prima proper mixture t rough economical objectv isto provide a out the range of service conditions corresponding to a given throttle position, that. is, assuming the mixture is of the economical the engine is or lean type when running under favorable conditions (as ywlien the vehicle is traveling at say twenty-five miles per' roads) hour on 4hard level it isthe purpose of the invention to provide a carburetor whereby the mixture ,is automatically enriched an increase in load. Still l immediately upon another object is to insure a proper mixing of the 'primary airy and fuel supply.

In the 4drawings, Fig. ltion showing a preferred 1 is a vertical secembo'diment of the invention. Fig. 2 is a perspective view ci the strangle tube, parte being broken away to show the blades or iins whereby niietture current is given a whirling movement." Fig. 3 is a perspective view of one ot'thei Si blades.

The general construction oi the carburetor to which the invention is shown 'sa' being. applied is well .known and includes the body 1 forming an air intake passage te 2 and a mixture outlet 3, concentric or a partof their length andseparai'zed by the cylindrical wall onslrirt or sleeve guide f. Attached to the body in any suitable man! ner is a co'ver for a iioatbowl 6, said cover 70 having a depressed central portion 7 forniti ing a nozzle chamber 8 and tapped to ceive the usual nozzle structure 9; and fuel is supplied in the ordinary Way through the medium of the passage l2, 4valve l@ and valve-controlling iioat le.

15 designates a strangle tube positioned lon the cover and extending down into the communication `between the annular passages 2 and 3 through the auxiliary air passage directly belou' the Wall 4 'whenthe il@ engine is not ruiming or when but little suc tion is applied to the outlet as in idling. This valve is provided with a iiirtiire 18 including a disc-like element or litplate 18' at its lower end, said element being srh- $6 ranged Ato rcstrict'the passage l? more or less depending on the 'position of the air' valve as Well as the taper oi the strangle tube 4. A retainer 2O clamped between the body and'the cover affords' a convenient mt means for holding the strangle tube in place, this plate-and the fiaiige 2l on the inner surface of the guide 'l serving to limit -the movement of the auxiliary air valve.

the chamber 17 and so arranged as to conduct but little, if any, air when the auxiliary air valve isiin the .position shown; that is, when the engine suction in the space ariterior to the throttle is low, as in idling, the

l valve or disc 18" restricts the tlowofair from below to such an extent that a relativelystrong pullis exercised on the idling passage'l-Q 'to secure the proper amount of l fuel. The throttle being gradually opened and the suction increasing, the lifte plate rises beyond the by-passpassages 26, and air pressure from the chamber a/ndI a certain amount of air is admitted into the :lessees 'be due to the tendency of the air valve to vibrate vertically and to thereby in eil'ect re strict the luy-pass passages.

'That is, in this manner l automatically secure a desirable rich mixture for idling,

Ia lean or economical mixture for intermespace below the disc or valve 18ancl tends.

passage 17, in other Words, to lean out the to more nearly satisfy' the suction in the,

mixture as obtained from the idling pas? sage; at the same time, however, the main nozzle Slf comes `into action but not so intensely as would be the case were the by-pass passages omitted. These latter thus tend to admit air from the passage 8 to the space'` diate throttled s eeds and a rich ower mixture for open throttle speeds, the. vtransition 9 from one to the other being so gradual as to give rise 'to unusual smoothness' of action or flexibility, Moreover, the character oi the'. mixture depends on the load tomas explained heretofore, the by-pass passages automatically cause the richness of the-mixture'to build up as the load is added and to`become less as the load decreases. it

*ivillalso be seen that the apparatus includes an air intake of which the chamber 8 forms a part, a mixture chamber 17 and a by-pass passage or passages Q6 lay-passing the noa-- zle, 9, together with means under the control of the engine suction for restrictingor 4otherwise, rendering the lay-pass relatively just above the nozzle 9 at the' intermediate throttled speeds to thereby reduce the lsuetion and establish a more lean or economical mixture for ordinary driving. At the same time, the, transition or change of mixture from the relatively rich to the relatively lean is so gradual as4 to result in a,

ihighly desirable .flexibility of operation,`

Assuming now thatthe throttle valv'econtinues to open and that `the suction further increases, more fuel is admitted from the jet 9 andmore auxiliary air enters 11nderneath the edge of the air valve as the vlatter rises; and the resultingmixture might become-too lean for maximum powerat `open I throttle Were it not Jor thefact that'the current oit air entering the chamber i7 under conditions `^0f open throttle andfhigh speed from arohnol the nozzle 9 iiows upl more' nearly' through the middle 4of the chamber and not directly across theoutlets of the bypass passages E26,4 from 'which it follows ,that a less quantity of air relatively to the total primary mixture, is bled in, and. a rise in richness. or atleast a proper 'maintenance oi the existing4 richness to afford, the' desirable power mixture takes place.

Again, assuming that the throttle remains at a given position, saythat, corresponding to a speed of thirty miles per hour on :tavorable roads, and the load 1s increased as in elimbinghille-of medium height, theair inoperative for the flow of air atV both low and high auctions, and particularly orcausing or permitting it to function freely' at suctions corresponding to the intermediate throttled engine speeds,

ln order that the fuel may be more 'fully broken up, l prefer to form on the inner surface of the strangle tube inclined or helicallgblades or tins, these elements being, in the 'present instance,lseparate from the tube itself and inset in slots formed therein. As.-

shown, they include the l'plane body portions 30 (the bases of which are received in the slots) having the inwardly extending projections 3l the upper corner portions 32 of Which'are bent forwardly in the direction of the inclination of the body portion. A The primary Vair `and fuel mixture is in eiect split up into seueralhchannels and is caused to whirl around in the mixing chamber to disintegrate the small 'uel globules and distribute ,'them throughout the entire cross section of the incoming; air.

Byproceeding in this manner the disintegrating influence is applied to much better advantage and 'the resulting mixture is much more homogeneous than would bethe case Were Athe fins or their equivalent positioned on the Wall of the mixing chamber beyond the inlet for tbe auxiliary air, since theywould .in that event operate-primarily on an envelope of air rat-her than on .the entering stream of fuel mixture.

l am aware that` the invention, both in respect to the -by-pass passage and to the lll! its

mixing blades or fins, is'a plicable to carburetois other than that s own, and I do not, therefore. wish to be limited except as indicated by the subjoined claims.

l'. A carburetor including a fuel chamber having a cover with adepression therein, a

strangle tube depending into the depression,

a fuel supply device leading from the fuel chamber and opening into the strangle tube, said strangle .tube and cover forming an air intake assagc leading down about the outside o the stran le tube and upwardly alon the nozzle, 'tige strangle tube forming a mixture passage for air from the intake passage and fuel from the nozzle and also aving a by-pass passage for b -passing the nozzle and permitting air to flbw frornthe intake to the mixture passage in said strangle tube to lean out the mixture at certain engine speeds, and movable means operatve on said by-pass passage to restrictv the flow of air therethrough at low engine speeds and to permit an increased flow of such air at intermediate engine speeds.

2. In a carburetor, a throttled mixture passage, means forA supplying primary a'ir trolled by said e ement, whereby the quality of the fuel mixture is varied in accordance with the engine load and without manipulation of the throttle.

3. In a carburetor, a casing, a main fuel inlet and an auxiliary fuel inlet spaced therefrom longitudinally of the. casing, a strangle tube into which said inlets open, said main fuel inlet being spaced from the strangle tube to afford an inlet for air into the latter, there being a passage through the strangle tube to by-pass themain fuel inlet and to admit pressure to the space immediately about the main fuel inlet and between it and said idling fuel inlet, and suction controlled incans for regulating the operation of said by-pass relatively to that of said air inlet.

4. In a carburetor, a throttled air passage having a restriction, a fuel' inlet opening into the air passage adjacent the restriction, a suction controlled lift4 plate arranged to restrictsaid restriction as the suction falls, and a by-pass passage opening into said air passage substantially opposite the lift plate when ,the latter is in lowermost position, whereby the quality of the fuel mixture is varied in accordance with the engineload and without manipulation of the throttle.

5. A carburetor including a strangle tube `apen at its lower end, a main nozzle ar- 4ranged to deliver lfuel to the lower portion thereof, an idling fuel passage opening into Said strangle tube beyond said main nozzle, a by-pass passage arranged to deliver air to said strangle tube below the upper end thereof and beyond rsaid main nozzle, and a suction controlled member interposed between said main nozzle and the outlet of said idling fuel passage and cooperating with said bypass passage to restrict the flow of air therethrough under certain conditions of suction.

6. A carburetor including a fuel chamber having a cover with a depression therein, a strangle tube depending into the depression, 'a main fuel nozzle leading from the fuel chamber and opening into the lower portion of said strangle tube, an idling -fuel passage opening into 'said strangle tube at a higher level than said main nozzle, said strangle tube and cover forming an air intake passage leadingdown about the out- .side of the strangle tube and upwardly past y'said nozzle and said idling fuel passage, said strangle tube having a by-pass passageV below the outlet of said idling fuel passage thereinto, a mixture outlet passage including a guide, a tubular air admitting valve slidable therein and having a lift plate therefor arranged to 'cooperate with lsaid by-pass passage to permit increased flow of air therethrough under conditions of interinedlate engine speed.

FRED E. ASELTINE. 

